The two tube stations I use most frequently both feature in the list of stations where the most money has wrongly been taken from people using Oyster cards.

The figures have been dug out by Liberal Democrat London Assembly member Caroline Pidgeon and show that £862,000 was wrongly taken off passengers at Oxford Circus in the last year and £248,000 at Finsbury Park.

Both are very busy stations, so their presence in the list of worst offenders may be partly caused by the number of passengers passing through, but even so it’s a good reminder about checking your Oyster transactions online every now and again. In fact, the last time I did this, I found a small over-charge. The phone help line were very good at helping to identify what the wrong charge had been and refunding it. That was some consolation – but I needed to know to query something with them in the first place.

In total £61.8m was wrongly taken last year. Caroline Pidgeon has said of these figures:

This level of overcharging is totally unacceptable. There is something very seriously wrong when each and every week of the year Londoners are ripped off by more than £1 million.

Of course in some cases passengers might forget to touch in and touch out, but such huge levels of overcharging clearly demonstrate that there are some structural problems with how Oyster is operating. It is clear that not enough is being done to ensure the machines and the technology are working properly.

TfL also need to take immediate steps to make it far easier for people to be able to claim a refund when they have been overcharged.

Above all else the levels of overcharging occurring need to be regularly published at every station, so that passengers are alerted to this serious problem.

So my tip? Check your Oyster transactions now and again to see if money has been wrongly taken.